1 /* Copyright (c) 2015, bugyo
2 * All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are met:
6 * 1. Redistributions of source code must retain the above copyright notice,
7 * this list of conditions and the following disclaimer.
8 * 2. Redistributions in binary form must reproduce the above copyright notice,
9 * this list of conditions and the following disclaimer in the documentation
10 * and/or other materials provided with the distribution.
11 *
12 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
13 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
14 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
15 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
16 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
17 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
18 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
19 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
20 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
21 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
22 */
23
24 #include <sys/cdefs.h>
25 #ifndef lint
26 __RCSID("$NetBSD: print-nsh.c,v 1.5 2024/09/02 16:15:32 christos Exp $");
27 #endif
28
29 /* \summary: Network Service Header (NSH) printer */
30
31 /* specification: RFC 8300 */
32
33 #include <config.h>
34
35 #include "netdissect-stdinc.h"
36
37 #define ND_LONGJMP_FROM_TCHECK
38 #include "netdissect.h"
39 #include "extract.h"
40
41 static const struct tok nsh_flags [] = {
42 { 0x2, "O" },
43 { 0, NULL }
44 };
45
46 /*
47 * 0 1 2 3
48 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
49 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
50 * |Ver|O|U| TTL | Length |U|U|U|U|MD Type| Next Protocol |
51 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
52 */
53 #define NSH_BASE_HDR_LEN 4
54 #define NSH_VER(x) (((x) & 0xc0000000) >> 30)
55 #define NSH_FLAGS(x) (((x) & 0x30000000) >> 28)
56 #define NSH_TTL(x) (((x) & 0x0fc00000) >> 22)
57 #define NSH_LENGTH(x) (((x) & 0x003f0000) >> 16)
58 #define NSH_MD_TYPE(x) (((x) & 0x00000f00) >> 8)
59 #define NSH_NEXT_PROT(x) (((x) & 0x000000ff) >> 0)
60
61 #define NSH_SERVICE_PATH_HDR_LEN 4
62 #define NSH_HDR_WORD_SIZE 4U
63
64 #define MD_RSV 0x00
65 #define MD_TYPE1 0x01
66 #define MD_TYPE2 0x02
67 #define MD_EXP 0x0F
68 static const struct tok md_str[] = {
69 { MD_RSV, "reserved" },
70 { MD_TYPE1, "1" },
71 { MD_TYPE2, "2" },
72 { MD_EXP, "experimental" },
73 { 0, NULL }
74 };
75
76 #define NP_IPV4 0x01
77 #define NP_IPV6 0x02
78 #define NP_ETH 0x03
79 #define NP_NSH 0x04
80 #define NP_MPLS 0x05
81 #define NP_EXP1 0xFE
82 #define NP_EXP2 0xFF
83 static const struct tok np_str[] = {
84 { NP_IPV4, "IPv4" },
85 { NP_IPV6, "IPv6" },
86 { NP_ETH, "Ethernet" },
87 { NP_NSH, "NSH" },
88 { NP_MPLS, "MPLS" },
89 { NP_EXP1, "Experiment 1" },
90 { NP_EXP2, "Experiment 2" },
91 { 0, NULL }
92 };
93
94 void
nsh_print(netdissect_options * ndo,const u_char * bp,u_int len)95 nsh_print(netdissect_options *ndo, const u_char *bp, u_int len)
96 {
97 uint32_t basehdr;
98 u_int ver, length, md_type;
99 uint8_t next_protocol;
100 u_char past_headers = 0;
101 u_int next_len;
102
103 ndo->ndo_protocol = "nsh";
104 /*
105 * 0 1 2 3
106 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
107 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
108 * | Base Header |
109 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
110 * | Service Path Header |
111 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
112 * | |
113 * ~ Context Header(s) ~
114 * | |
115 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
116 */
117
118 /* print Base Header and Service Path Header */
119 if (len < NSH_BASE_HDR_LEN + NSH_SERVICE_PATH_HDR_LEN) {
120 ND_PRINT(" (packet length %u < %u)",
121 len, NSH_BASE_HDR_LEN + NSH_SERVICE_PATH_HDR_LEN);
122 goto invalid;
123 }
124
125 basehdr = GET_BE_U_4(bp);
126 bp += 4;
127 ver = NSH_VER(basehdr);
128 length = NSH_LENGTH(basehdr);
129 md_type = NSH_MD_TYPE(basehdr);
130 next_protocol = NSH_NEXT_PROT(basehdr);
131
132 ND_PRINT("NSH, ");
133 if (ndo->ndo_vflag > 1) {
134 ND_PRINT("ver %u, ", ver);
135 }
136 if (ver != 0)
137 return;
138 ND_PRINT("flags [%s], ",
139 bittok2str_nosep(nsh_flags, "none", NSH_FLAGS(basehdr)));
140 if (ndo->ndo_vflag > 2) {
141 ND_PRINT("TTL %u, ", NSH_TTL(basehdr));
142 ND_PRINT("length %u, ", length);
143 ND_PRINT("md type %s, ", tok2str(md_str, "unknown (0x%02x)", md_type));
144 }
145 if (ndo->ndo_vflag > 1) {
146 ND_PRINT("next-protocol %s, ",
147 tok2str(np_str, "unknown (0x%02x)", next_protocol));
148 }
149
150 /* Make sure we have all the headers */
151 if (len < length * NSH_HDR_WORD_SIZE) {
152 ND_PRINT(" (too many headers for packet length %u)", len);
153 goto invalid;
154 }
155
156 /*
157 * 0 1 2 3
158 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
159 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
160 * | Service Path Identifier (SPI) | Service Index |
161 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
162 *
163 */
164 ND_PRINT("service-path-id 0x%06x, ", GET_BE_U_3(bp));
165 bp += 3;
166 ND_PRINT("service-index 0x%x", GET_U_1(bp));
167 bp += 1;
168
169 /*
170 * length includes the lengths of the Base and Service Path headers.
171 * That means it must be at least 2.
172 */
173 if (length < 2) {
174 ND_PRINT(" (less than two headers)");
175 goto invalid;
176 }
177
178 /*
179 * Print, or skip, the Context Headers.
180 * (length - 2) is the length of those headers.
181 */
182 if (ndo->ndo_vflag > 2) {
183 u_int n;
184
185 if (md_type == MD_TYPE1) {
186 if (length != 6) {
187 ND_PRINT(" (length for the MD type)");
188 goto invalid;
189 }
190 for (n = 0; n < length - 2; n++) {
191 ND_PRINT("\n Context[%02u]: 0x%08x", n, GET_BE_U_4(bp));
192 bp += NSH_HDR_WORD_SIZE;
193 }
194 past_headers = 1;
195 } else if (md_type == MD_TYPE2) {
196 n = 0;
197 while (n < length - 2) {
198 uint16_t tlv_class;
199 uint8_t tlv_type, tlv_len, tlv_len_padded;
200
201 tlv_class = GET_BE_U_2(bp);
202 bp += 2;
203 tlv_type = GET_U_1(bp);
204 bp += 1;
205 tlv_len = GET_U_1(bp) & 0x7f;
206 bp += 1;
207 tlv_len_padded = roundup2(tlv_len, NSH_HDR_WORD_SIZE);
208
209 ND_PRINT("\n TLV Class %u, Type %u, Len %u",
210 tlv_class, tlv_type, tlv_len);
211
212 n += 1;
213
214 if (length - 2 < n + tlv_len_padded / NSH_HDR_WORD_SIZE) {
215 ND_PRINT(" (length too big)");
216 goto invalid;
217 }
218
219 if (tlv_len) {
220 const char *sep = "0x";
221 u_int vn;
222
223 ND_PRINT("\n Value: ");
224 for (vn = 0; vn < tlv_len; vn++) {
225 ND_PRINT("%s%02x", sep, GET_U_1(bp));
226 bp += 1;
227 sep = ":";
228 }
229 /* Cover any TLV padding. */
230 ND_TCHECK_LEN(bp, tlv_len_padded - tlv_len);
231 bp += tlv_len_padded - tlv_len;
232 n += tlv_len_padded / NSH_HDR_WORD_SIZE;
233 }
234 }
235 past_headers = 1;
236 }
237 }
238 if (! past_headers) {
239 ND_TCHECK_LEN(bp, (length - 2) * NSH_HDR_WORD_SIZE);
240 bp += (length - 2) * NSH_HDR_WORD_SIZE;
241 }
242 ND_PRINT(ndo->ndo_vflag ? "\n " : ": ");
243
244 /* print Next Protocol */
245 next_len = len - length * NSH_HDR_WORD_SIZE;
246 switch (next_protocol) {
247 case NP_IPV4:
248 ip_print(ndo, bp, next_len);
249 break;
250 case NP_IPV6:
251 ip6_print(ndo, bp, next_len);
252 break;
253 case NP_ETH:
254 ether_print(ndo, bp, next_len, ND_BYTES_AVAILABLE_AFTER(bp), NULL, NULL);
255 break;
256 default:
257 ND_PRINT("ERROR: unknown-next-protocol");
258 return;
259 }
260
261 return;
262
263 invalid:
264 nd_print_invalid(ndo);
265 }
266
267